Covering-thread mechanism for sewing-machines



e. s. GATCHELL. v COVERING THREAD MECHANISM FOR SEWING MACHINES.

- APPLICATION FILEDMAR, 18. I918. 1,365,238. Patented Jan. 11, 1921.

, a SHEETSSHEET WITN ESSE S INVE TOR wj .7

ATTORNEY G. S. GATCHELL.

COVERING THREAD MECHANISM FOR SEWING MACHINES- APPLICATION FILED MAR. 18. I9I8.

Patented Jan. 11,1921.

INVEN 0R WITNESSES 5&4

G. S. GATCHELL.

COVERING THREAD MECHANISM FOR SEWING MACHINES.

APPLICATION FILED man, l8. ms.

1,365,238. Patented Jan. 11,1921.

3 SHEETS-SHEEI 3- UlTED srai gsrarsa'r OFFICE.

GEORGE S. GATCHELL, OF BOSELLE PARK, NEW" JERSEY, ASSIGNOR TO THE SINGER MANUFACTURING- COM IPANY, A

CORFBOBATION OF NEW JERSEY. l

COVERING-THREAD MEGHANKSM non snwrne-Mnonrivizs.

Specification of Letters Patent. Patented Jan, 11, 1921. Original application filed August 10,1917, Serial No. 185,446. Divided and this application filed M iarch 18, 1918. Serial No. 223,112.

To all to 7mm it wmy concern Be it known that I, Gnonen S. GATCHELL a citizen of the United States, residing at Roselle Park, in the county of Union and State of New Jersey, have'invented certain new and useful Improvements in Covering- Thread Mechanisms for sewing Machines, of which the following is a specification, ref erence being had therein to the accompanying drawings.

This invention relates to sewing machines and has for an object to provide a simplified and improved mechanism for laying one or more covering threads back and forth across the line of seam-formation.

A further object of the invention isto provide a covering thread mechanism which will take up a minimum of space in front of the stitching point and which will avoid the crossing of the covering threads above the thread-fingers and in front of the needles which has heretofore interfered with the threading of the needle or needles of the machine. i

In its preferred form, the invention is embodied in a multiple-needle sewing machine disclosed in my co-pending application Serial No. 185,4c46, filed August 10, 1917, of which this application is a division, and comprises a pair of thread-finger levers fulcrumed upon a fixed bushing in which the presser-bar is journaled forrising and falling movements. The thread-finger levers extend away from the presser-bar in opposite directions transversely of the line of seam formationand are socketed at their free ends to receive the vertically extending shanks of corresponding thread-fingers, the horizontally disposed blades ofvwhich are curved to the same radius concentrically with the presser-bar and are arranged one above the other at an elevation slightly above the presser-fo ot of'the machine, the radius of oscillation of the thread-fingers being such that their blades are adapted to cross the line of seam closely in frontofthe stitching point.

The actuating mechanism for the threadfingers imparts to the latter one complete oscillation for each two reciprocations of the needles. During their oscillation the threadfingers are preferably moved simultaneously in opposite directions across the line of seam formation while the needles are 1n the invention.

work and are caused to slow up or dwell in their extreme positions as the work is being fed and as the needles are, in effect, stepping over the cross-threads leading from the eyes at the extremities of the thread-fingers to the last stitch. in the present thread-finger mechanism, the covering threads are led downwardly alongside the machine head to the thread-fingers and thence forwardly and inwardly to the stitching point. The threading of the needles is therefore not interfered with by either the covering threads or the thread-fingers.

In the accompanying drawings, Figure l is a side elevation, partly in section, of a chain-stitch sewing machine embodying the Fig- 2 is a reverse side elevation of the machine. Fig. 3 is ahorizontal section through the presser-bar showing the thread-finger mechanism in plan. Fig. 4; is a front elevation of the thread-fingers and other mechanism adjacent the stitching point. Fig. 5 is a perspective view of the same and Fig. 6 is a sectional view of the supporting sleeve and thread-finger levers fulcrumed thereon.

In the preferred embodiment of the invention, as illustrated, the machine frame comorises the hollow base 1 from which rises the standard 2 of the overhanging bracketarni 3 terminating in the hollow head 4. Secured to the standard 2 is the flanged rearward extremity of the tubular work-arm 5 within which are mounted the looper 6, the main and auxiliary feed-dogs 7 and 8, re spectively, and their actuating devices which may be of any suitable construction but which are preferably constructed substantially in accordance with the disclosure of my said copending application.

The main-shaft 9 extends transversely of the standard 2 and is formed with a bellcrank 10 connected by pitman 11 to the ballended pin 12 at the extremity of the crankarm 13 fixed to the rear end of the oscillating needle-driving shaft 1th to the forward end of which is secured a crank 15 connected by tie usual link 16 to the needle-bar 17 carrying, in the present instance, four needles n m n and n with which the looper 6 coiiperates in the usual manner to form stitches. 1

The Presser-bar 18 of the machine is ournaled to slide within the bushing 19 fixed within an aperture at the lower end of the head 1. Secured to the lower end of the presser-bar 18 is the presser-foot shank 20 to which is pivoted at 21 the presser-foot sole-piece 22 which presses the work against the throat-plate 23 and feed-dogs 7 and 8. The presser-foot sole-piece 22 is bifurcated to form spaced toes between which upturned margins of material are adapted to pass to the trimming mechanism which preferably comprises the cooperating shearing blades 24 and 25 mounted and operated substan tially as described in my said copending application; a throw-out trimming chute 26 being provided to deflect the trimmings to one side, as shown in Fig. 5.

The covering threads to be incorporated in the upper side of the seam are presented by a pair of L-shaped thread-fingers having curved horizontally disposed blades 27 and vertically arranged shanks 28; the latter being secured in socketed bosses 29 at the free ends of the thread-finger carrying levers 30 the opposite apertured ends of which are fulcrumed upon the lower reduced end of the bushing or sleeve 19 surrounding the presser-bar, as shown in Fig. 6. The threadfinger blades 27 are preferably curved to the same radius concentrically with the presser-bar and are formed at their free extremities with thread-delivering eyes 31 which are connected by thread-grooves 32 with the thread-eyes 33 at the lower ends of the vertical shanks 28. The blades of the thread-fingers operate in planes one slightly above the other as shown best in Fig. 4-. Simultaneous oscillatory movements in opposite directions are imparted to the levers 30 by means of the links 34 which connect the latter with one arm of a bellcranklever fulcrumed on the headed pin 36 carried by the head 4t. The other arm 35 of the bellcrank-lever carries a ball-ended pin 37 which. is connected by a link 38 to a ballended pin 39 carried by the lower end of the depending arm 40 clampedto the front end of the rock-shaft 11 journaled at the side of the bracket-arm in the bearing lugs 42. The rear end of the shaft l1 carries a crank-arm 43 which projects into the standard 2 through an opening a l in the side of the latter and is connected by a balland-socket joint to the upper end of the pitman 15 actuated by a ball-eccentric 46 on the hollow counter-shaft 17 journaled on the fixed pin 18 in parallelism with the mainshaft 9 and driven by the latter through two-to-one speed-reducing gears 4L9, Fig. 1. The thread-fingers are thus actuated backand-forth across the line of seam in front of the needles at one-half the frequency of reciprocation of the needles, so that each thread-finger presents its thread to the needles alternately at opposite sides of the line of seam. It will now be appreciated that when the trimming chute 26 is shifted to inoperative position, Fig. 3, the thread fingers and needles will be exposed and may readily be threaded. Moreover the covering threads are never crossed in front of the needles at an elevation above the threadfingers.

By referring to Fig. 1, it will be seen from the position of the crank 10 and eccentric 46 that the thread-fingers are just approaching but have not quite reached one of their extreme positions whilethe needle-bar is at the end of its up stroke. As a result, the threadfingers have a very slow movement, amounting practically to a dwell, as the needle points are beginning their descent in front of the cross-threads leading from the threadfinger eyes 31 to the work,-Fig. 5. This dwell of the thread-finger continues until the points of the needles have passed safely down in front of the cross-threads.

Having thus set forth the nature of the invention, what I claim herein is- 1. A sewing machine comprising in combination, stitch-forming mechanism including a reciprocating needle, and a pair of oscillatory thread-fingers supported in rear of the stitching point at a fixed elevation independently of the presser-bar, said threadfingers having horizontally disposed blades curved throughout their entire length to substantially the same radius concentric with the center of oscillation and arranged one above the other to cross the line of seam in front of the stitching point.

2. Covering threadmechanism for sewing machines comprising, a resser-bar, a pair of levers fulcrumed concentrically with and supported at a fixed elevation independently of the resser-bar, a pair of L-shaped threadfingers each carried by a corresponding one of said levers, each of said thread-fingers comprising a vertical shank and a horizontally disposed blade curved substantially concentrically with the axis of oscillation of its respective supporting lever and having a thread-receiving eye adjacent the vertical shank and a thread-delivering eye at its free end, said blades operating in different planes one above the other, and means for oscillating said levers simultaneously in opposite directions.

In testimony whereof, I have signed my name to this specification.

GEORGE S. GATCHELL. 

